1. Field of the Invention
The present invention generally relates to a satellite data distribution method and system using a mobile communication system and, more particularly, to a satellite data distribution method and system for distributing data to a base station of a mobile communication system and subscribers of the mobile communication system substantially at the same time by providing a satellite communication receiver to the base station of the mobile communication system.
The satellite data distribution, which distributes data to a base station of a mobile communication system and subscribers of the mobile communication system substantially at the same time, may be referred to as a remote loading system for a base station of a mobile communication system via a satellite.
2. Description of the Related Art
The satellite data distribution system serves to distribute data to a number of subscribers of the system. The satellite data distribution system has become popular as one of multi-media services. Particularly, the satellite data distribution system has an advantage to distribute data simultaneously over a large area as compared to other data distribution systems such as a cable communication system or a ground area radio communication system.
FIG. 1 is an illustration for explaining a conventional wide area data distribution system using satellite communication. The conventional satellite data distribution system can provide an interactive data distribution service. A host center 10 stores various sets of data including application data, and can transmit a large amount of data to a number of subscriber terminals 20 or to a predetermined subscriber terminal via a satellite 1.
The host center 10 has a satellite antenna such as a parabola antenna or a Cassegrain antenna so as to transmit data to the satellite 1. Each of the subscriber terminals 20 includes a receiver unit and a satellite communication antenna to receive the data transmitted by the satellite 1.
In the procedure of the conventional data distribution service, a subscriber (which corresponds to an individual user or a company) requests a distribution of data to the host center 10 via a ground surface network. The host center 10 responds to the subscriber""s request to distribute the requested data to the subscriber. A user of this system can use various services through a personal computer, for example, which is connected to the receiver unit.
However, the above-mentioned conventional data distribution system has a problem in that each of the subscribers must have the satellite communication receiver unit and the satellite communication antenna which requires a relatively large construction. Thus, a company or an individual user cannot easily install the receiver unit and the satellite antenna which is a bottleneck for spreading the data distribution service using a satellite.
It is a general object of the present invention to provide an improved and useful satellite data distribution method and system in which the above-mentioned problems are eliminated.
A more specific object of the present invention is to provide a satellite data distribution method and system in which a subscriber can receive a data distribution service via a mobile communication system.
Another object of the present invention is to provide a satellite data distribution method and system for efficiently distributing loading data to a plurality of base stations of a mobile communication system via a satellite.
In order to achieve the above-mentioned objects, there is provided according to one aspect of the present invention a satellite data distribution method for distributing data to a plurality of subscribers of a satellite data distribution system via a satellite, the satellite data distribution system including a mobile communication system having at least one base station unit communicating with the subscribers, the satellite data distribution method comprising the steps of:
a) transmitting data to be distributed from a center station of the satellite data distribution system to the satellite;
b) distributing the data from the satellite to the base station unit of the mobile communication system; and
c) distributing the data from the base station unit to the subscribers.
According to the above-mentioned invention, the data to be distributed to the subscribers is relayed by the base station unit of the mobile communication system. The data transmitted from the satellite is collectively received by the base station unit, and then the data is distributed to each of the subscribers via the radio communication used in the mobile communication system. Thus, a satellite data reception unit is not necessarily provided to each of the subscribers.
In the satellite data distribution method according to the present invention, the base station unit of the mobile communication system may be connected to the center station via a communication network, and may further comprise the step of:
d) sending a distribution request from one of the subscribers to the center station via the mobile communication network and the communication network, the distribution request requesting distribution of the data.
In the above-mentioned invention, step a) may include the step of:
a-1) transmitting the data from the center station to the base station unit of the mobile communication system via the satellite in response to the distribution request from the one of the subscribers.
Additionally, step d) may comprise the step of:
d-1) sending a closing request to the mobile communication system for requesting closing of a communication channel used for distributing the data while the data is being distributed to the subscribers after the distribution request from one of the subscribers is confirmed in the base station unit.
Thus, the mobile communication network can always recognize available channels which are not used for the satellite distribution data, and thus an effective channel assignment can be performed in the mobile communication system.
In the satellite data distribution method according to the present invention, step d) may comprise the step of:
d-2) setting a reception frequency in the base station unit for receiving the data from the satellite after confirming the distribution request from the subscribers during a communication between the one of the subscribers and the center station.
Step d) may further comprise the step of:
d-3) transferring information from the one of the subscribers to the base station unit, the information including the reception frequency and a subscriber number of the one of the subscribers.
Additionally, step c) may comprise the steps of:
c-1) automatically making a call from the base station unit to the one of the subscribers based on the information transferred in step d-3); and
c-2) automatically disconnecting a connection between the base station unit and the one of the subscribers after the data is distributed from the base station unit to the one of the subscribers.
In the above-mentioned invention, the calling operation and disconnecting operation are automatically performed by the base station unit, resulting in reduction in the control operations performed by the mobile communication system.
The satellite distribution method according to the present invention may further comprise the step of:
e) sending to the one of the subscribers a message indicating that a distribution of the data is unable when the data is not received from the satellite within a predetermined time period after the distribution request is sent from the one of the subscribers.
Additionally, there is provided according to another aspect of the present invention a base station unit of a mobile communication system used in a satellite data distribution system distributing data to a plurality of subscribers via a satellite, the base station unit comprising:
a communication processing unit for connecting the subscribers to the mobile communication system;
a satellite data reception unit for receiving the data from the satellite; and
a distribution processing unit for distributing the data received by the satellite data reception unit, the data being distributed to the subscribers via the communication processing unit.
Additionally, there is provided according to another aspect of the present invention a base station unit of a mobile communication system used in a satellite data distribution system distributing data to a plurality of subscribers via a satellite, the base station unit comprising:
a communication processing unit for connecting the subscribers to the mobile communication system; and
a distribution processing unit connectable to a satellite data reception unit for receiving the data from the satellite, the distribution processing unit distributing the data received by the satellite data reception unit, the data being distributed to the subscribers via the communication processing unit.
According to the above-mentioned invention, the data to be distributed to the subscribers is relayed by the base station unit of the mobile communication system. The data transmitted from the satellite is collectively received by the satellite data reception unit, and then the received data is distributed to each of the subscribers via the distribution processing unit provided in the base station unit of the mobile communication system. Thus, a satellite data reception unit is not necessarily provided to each of the subscribers.
The base station unit may further comprise a data throughput control unit controlling throughput of the data when the data is received by the satellite data reception unit.
Additionally, the communication processing unit may have a channel exclusive for distributing the data received by the satellite data reception unit to the subscribers.
Further, the communication processing unit may comprise a channel assignment control unit for flexibly assigning one of a plurality of communication channels to distribute the data to the subscribers in response to a condition of use of the communication channels.
Additionally, the communication processing unit may comprise a channel control unit which sends a close request for closing one of a plurality of communication channels used for distributing the data while the data is being distributed to the subscribers, the close request being sent to the mobile communication system after a distribution request from one of the subscribers is confirmed, the distribution request requesting distribution of the data to the one of the subscribers.
The communication processing unit may comprise a frequency control unit which sets a reception frequency of the satellite data reception unit upon confirmation of reception of a distribution request during communication between one of the subscribers sending a distribution request and a center station of the satellite data distribution system, the distribution request requesting for distributing the data to the one of the subscribers.
Additionally, the communication processing unit may further comprise a reception control unit which receives information from the one of the subscribers during a communication between the one of the subscribers and the center station of the satellite data communication system, the information including the reception frequency and a subscriber number of the one of the subscribers.
The communication processing unit may further comprise a disconnection control unit which automatically disconnects a connection between the base station unit and the one of the subscribers after distributing the data to the one of the subscribers by automatically calling the one of the subscribers based on the subscriber number included in the information.
The base station unit according to the present invention may further comprise a packet processing unit for converting the data into packet data when the data received from the satellite is transmitted to the subscribers.
Additionally, the base station unit according to the present invention may further comprise a message control unit which sends an unable message to one of the subscribers requesting distribution of the data when the data is not received within a predetermined time period after a distribution request is received from the one of the subscribers, the unable message indicating that the data is not distributed from the base station unit, the distribution request requesting for distribution of the data to the one of the subscribes.
Additionally, there is provided according to another aspect of the present invention a satellite data reception unit provided in a base station unit of a mobile communication system used in a satellite data distribution system distributing data to a plurality of subscribers via a satellite, the satellite data reception unit comprising:
a data reception unit for receiving the data transmitted from the satellite; and
an interfacing unit for connecting the satellite data reception unit to a communication processing unit provided in the base station unit so as to connect the subscribers to the mobile communication system.
According to the above-mentioned invention, the data to be distributed to the subscribers is relayed by the base station unit of the mobile communication system. The data transmitted from the satellite is collectively received by the satellite data reception unit, and then the received data is distributed to each of the subscribers via the communication processing unit through the mobile communication system. Thus, a satellite data reception unit is not necessarily provided to each of the subscribers.
The satellite data reception unit according to the present invention may further comprise a data throughput control unit for controlling a throughput of the data when the data is received by the satellite data reception unit.
Additionally, the satellite data reception unit may further comprise a data storing unit for storing the data.
Further, the satellite data reception unit may further comprise a comparing unit for comparing a first subscriber number included in the data with a second subscriber number stored in the satellite data reception unit, the second subscriber number being included in information received from one of the subscribes sending a distribution request for requesting distribution of the data to the one of the subscribers, distribution of the data to the one of the subscribers being determined as a result of comparison performed by the comparing unit.
Additionally, there is provided according to another aspect of the present invention a mobile terminal unit of a mobile communication system adapted to be used with a satellite data distribution system distributing data to a plurality of subscribers via a satellite, the mobile terminal unit comprising:
a communication processing unit for communicating with a base station unit of the mobile communication system; and
a control unit for controlling a communication between the communication processing unit and a center station of the satellite data distribution system transmitting the data to the satellite, the control unit controlling transmission of a distribution request to be sent to the center station for requesting distribution of the data to the subscribers, the control unit further controlling an announcement of transfer of a reception frequency to the base station during the communication.
According to the above-mentioned invention, each of the subscribers is provided with the mobile terminal unit. One of the subscribers can request distribution of the data via the mobile terminal unit and the mobile communication system. The data requested by the one of the subscribers is transmitted from the center station to the satellite, and then the data is distributed to the subscribers via the base station unit of the mobile communication system. That is, the data transmitted from the satellite is collectively received by the base station unit, and then the data is distributed to each of the subscribers via the radio communication used in the mobile communication system. Thus, a satellite data reception unit is not necessarily provided to each of the subscribers.
The mobile terminal unit according to the present invention may further comprise:
a packet processing unit for converting the data into packet data when the data from the satellite is received from the base station; and
a selection unit for switching between the packet data and regular audio data when a communication is performed between the mobile terminal unit and the base station terminal.
Additionally, there is provided according to another aspect of the present invention a satellite data distribution method for distributing control software data to a plurality of base stations of a mobile communication system used with a satellite data distribution system via a satellite, the satellite data distribution method comprising the steps of:
a) transmitting the control software data from a center station of the satellite data distribution system to the satellite, the control data being used by the base stations so as to control the mobile communication system;
b) distributing the control software data from the satellite to the base stations; and
c) downloading the control software data received by the base station.
In the above-mentioned invention, the control software data (application software) can be simultaneously distributed to each of the base station units of the mobile communication system. Thus, the time spent on loading the application software data to the base station units is reduced. A maintenance function is also improved since the communication with each of the base station units is performed via the satellite.
In the satellite data distribution method according to the present invention, step c) may comprise the step of:
c-1) storing the control software data in a memory so that the control software data received from the satellite is stored separately from control software data currently used by the base stations.
The satellite data distribution method according to the present invention may further comprise the step of:
d) switching the currently used control software data to the control software data stored in the memory by sending a switch signal from the center station to the base stations via the satellite so that the currently used control software data is simultaneously switched to the control software data stored in the memory in each of the base stations.
Additionally, there is provided according to another aspect of the present invention a base station unit of a mobile communication system used with a satellite data distribution system, the base station unit using control software data to control the mobile communication system, the base station unit comprising;
a communication processing unit for connecting the base station unit to the mobile communication system;
a satellite data reception unit for receiving the data including control software data used for controlling the mobile communication system; and
a loading unit for loading the control software data received by the satellite data reception unit to the communication processing unit.
In the above-mentioned invention, the control software data (application software) can be simultaneously distributed to each of the base station units of the mobile communication system, and the distributed control software data is loaded to the communication processing unit. Thus, the time spent on loading the control software data to the base station units is reduced. A maintenance function is also improved since the communication with each of the base station units is performed via the satellite.
In the base station unit according to the present invention, the loading unit comprises a first memory and a second memory, the control software data received by the satellite data reception unit being stored in one of the first and second memories so that the control software data stored in the one of the first and second memories is switched to control software data previously stored in the other one of the first and second memories.
Additionally, there is provided according to another aspect of the present invention a processor readable medium having program code instructions stored thereon which when executed by a processor controls an operation of a base station unit of a mobile communication system used with a satellite data distribution system to simultaneously distribute data to a plurality of subscribers via a satellite, the instructions comprising:
communication control program means for causing the processor to connect the subscribers to the mobile communication system;
call connection management program means for causing the processor to automatically call one of the subscribers requesting the data after the base station unit receives the data from the satellite;
satellite data reception control program means for causing the processor to manage a reception of the data from the satellite; and
satellite IO managing program means for causing the processor to manage a connection of the satellite data reception unit to the base station, the satellite data reception unit receiving the data from the satellite.
In the processor readable medium according to the present invention, the satellite managing program means may include download reception processing program means for causing the processor to download control software data to a plurality of the base station units.
Additionally, the communication control program means may comprise:
radio IO management program means for causing the processor to manage input/output operations through radio communication;
operating system program means for causing the processor to control an operating system;
application program means for causing the processor to manage an operation with respect to an application; and
network management program means for causing the processor to manage a connection to a network.
Other objects, features and advantages of the present invention will become more apparent from the following detailed descriptions when read in conjunction with the accompanying drawings.